Ion implantation systems are sophisticated systems that are employed in fabricating semiconductor devices including flash memory, system on chip devices, central processor units, and the like. Ion implantation systems are employed during semiconductor device fabrication to selectively implant ions and control device behavior in a process referred to as ion implantation. Ion implantation systems rely on proper performance of their constituent parts in order to properly perform ion implantation and, as a result, properly fabricate semiconductor devices.
Shortening cycle times to fabricate semiconductors is critical to the success of semiconductor manufacturing. A key factor in cycle time is the movement of semiconductor workpieces from the equipment front end module (EFEM), at ambient pressure, into a load lock area, for vacuum pump down, and subsequently into the vacuum processing chamber, for example. Shortened cycle times are critical to operational success allowing lean manufacturing, lean inventory, better yields, less equipment downtime, and the like. One method of shortening cycle times involves adding wafer presence detection into the wafer handling system. This allows the system to proceed from one step to the next as soon as it has validated the presence or absence of a wafer.
In addition to shortening cycle times, wafer presence detection allows the wafer handling system to “recognize” when a wafer has been dropped or mishandled, so that the system can be interrupted, an operator can be notified, and the like. Without such “recognition”, wafers can be dropped or mishandled and can cause extensive damage to the system. This can cause contamination to subsequent wafers, result in reduced production yields, take a system out of production, result in costly repairs, etc.
Although there are many benefits to adding wafer presence detection in the wafer handling system, wiring a sensor to a power supply within the vacuum processing chamber significantly increases the complexity of the detection system. For example, adding powered wafer presence detection sensors to the wafer transfer arm would require major design changes. Thus, it is desirable to provide a method for allowing the remote detection of wafers within the vacuum processing chamber that does not require a dedicated power supply in the vacuum chamber.